根据区域和事件类型代码获取最近的事件

Question

我有以下json数据，如何通过在python中对startTime进行排序来获取基于区域和事件类型代码的最新记录以及最新事件？需要忽略事件类型代码的重复项。 有什么方法可以在 python 中比较这个startTime，找出哪个是最近的记录并只返回该记录？

示例数据：

"ResponseMetadata": {
"HTTPHeaders": {
"content-length": "1478",
"content-type": "application/x-amz-json-1.1",
"date": "Mon, 27 Jan 2020 21:24:47 GMT",
"x-amzn-requestid": "a84471fc-8bde-4404-854e-c1656884cac5"
},
"HTTPStatusCode": 200,
"RequestId": "a84471fc-8bde-4404-854e-c1656884cac5",
"RetryAttempts": 0
},
"events": [
{
"eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",
"startTime": "2020-01-15 11:50:00-06:00",
"region": "us-east-1"
},
{
"eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",
"startTime": "2019-11-26 02:59:00-06:00",
"region": "us-east-1"
},
{
"eventTypeCode": "AWS_TRUSTEDADVISOR_OPERATIONAL_NOTIFICATION",
"startTime": "2020-01-27 12:36:00-06:00",
"region": "us-east-1"
},
{
"eventTypeCode": "AWS_TRUSTEDADVISOR_OPERATIONAL_NOTIFICATION",
"startTime": "2019-11-18 16:04:00-06:00",
"region": "us-east-1"
},
{
"eventTypeCode": "AWS_MARKETPLACE_OPERATIONAL_NOTIFICATION",
"startTime": "2019-11-11 11:30:00-06:00",
"region": "us-east-1"
},
{
"eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",
"startTime": "2020-01-10 11:55:00-06:00",
"region": "us-west-1"
},
{
"eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",
"startTime": "2019-11-13 02:15:00-06:00",
"region": "us-west-1"
},
]
}

预期产出：

"eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",
"startTime": "2020-01-15 11:50:00-06:00",
"region": "us-east-1"
},
{
"eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",
"startTime": "2020-01-10 11:55:00-06:00",
"region": "us-west-1"
}
{
"eventTypeCode": "AWS_MARKETPLACE_OPERATIONAL_NOTIFICATION",
"startTime": "2019-11-11 11:30:00-06:00",
"region": "us-east-1"
},
{
"eventTypeCode": "AWS_TRUSTEDADVISOR_OPERATIONAL_NOTIFICATION",
"startTime": "2019-11-18 16:04:00-06:00",
"region": "us-east-1"
}

Answer 1

import datetime as dt
from dateutil.parser import parse
import json
def events_equal(event1, event2):
return event1["eventTypeCode"] == event2["eventTypeCode"] and event1["region"] == event2["region"]
json_data = ### Insert your json data string here ###

parsed_json_data = json.loads(json_data)
filtered_events = []
for parsed_event in parsed_json_data["events"]:
already_present = False
## for every event, check if we've already added it to the filtered list
for filtered_event_index in range(len(filtered_events)):
if events_equal(parsed_event, filtered_events[filtered_event_index]):
already_present = True
## Convert startTime strings to datetime object for comparison
parsed_event_date = parse(parsed_event["startTime"])
filtered_event_date = parse(filtered_events[filtered_event_index]["startTime"])
## Use parse if on an older version of python, otherwise
## strptime can handle the conversion
## parsed_event_date = dt.datetime.strptime(parsed_event["startTime"], '%Y-%m-%d %H:%M:%S%z')
## filtered_event_date = dt.datetime.strptime(filtered_events[filtered_event_index]["startTime"], '%Y-%m-%d %H:%M:%S%z')
if parsed_event_date > filtered_event_date:
## if parsed event date is newer, replace the one already present
filtered_events[filtered_event_index] = parsed_event
if not already_present:
filtered_events.append(parsed_event)
## build the new json object
filtered_events = {"events": filtered_events}
print(json.dumps(filtered_events, indent=4))

输出：

{
"events": [
{
"eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",
"startTime": "2020-01-15 11:50:00-06:00",
"region": "us-east-1"
},
{
"eventTypeCode": "AWS_TRUSTEDADVISOR_OPERATIONAL_NOTIFICATION",
"startTime": "2020-01-27 12:36:00-06:00",
"region": "us-east-1"
},
{
"eventTypeCode": "AWS_MARKETPLACE_OPERATIONAL_NOTIFICATION",
"startTime": "2019-11-11 11:30:00-06:00",
"region": "us-east-1"
},
{
"eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",
"startTime": "2020-01-10 11:55:00-06:00",
"region": "us-west-1"
}
]
}

这只能从 python 3.7 开始工作，早期版本的 strptime 只会以-0600的形式解析 UTC 偏移量，而不是-06:00。

编辑：我用dateutil解析器替换了strptime调用，它将适用于早期版本的python。